If you think Ki is a magical force, then you have fallen for some depiction of Ki which is NOT consistent with Aikido. Ki is the combination of intent focus and neuromuscular coordination in harmony. I'll accept the magic of Ki only as the kind of magic demonstrated and taught by Penn and Teller.

So, for the pencil trick challenge, I propose something like this: atemi with two hands to your eyes until you blink, and then I'd kiai as one hand sneaks down to pick up the pencil and deposit neatly in your shirt pocket before both hands tap your temples and withdraw. I'm not a magician, who is a PERFORMER of magic, but I do understand how magic really works, and it is totally about harmonizing with the audience, stealing their focus, and making room to facilitate the technical details... where else have I seen that?